Engagement of the Fas receptor has been reported to induce ceramide generation via
activation of acidic sphingomyelinase (aSMase). However, the role of aSMase in Fas-
mediated cell death is controversial. Using genetically engineered mice deficient in the
aSMase gene (aSMase−/−), we found that thymocytes, concanavalin A-activated T cells, and
lipopolysaccharide-activated B cells derived from both aSMase−/− and aSMase+/+ mice
were equally sensitive to Fas-mediated cell death, triggered by either anti-Fas antibody or …